July 13th 2022

Exoplanet WASP-96 b Atmospheric Characteristics

Graphic showing atmospheric components of distant gas giant planet.

A transmission spectrum made from a single observation using Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) reveals atmospheric characteristics of the hot gas giant exoplanet WASP-96 b.

A transmission spectrum is made by comparing starlight filtered through a planet’s atmosphere as it moves across the star, to the unfiltered starlight detected when the planet is beside the star. Each of the 141 data points (white circles) on this graph represents the amount of a specific wavelength of light that is blocked by the planet and absorbed by its atmosphere.

Graphic showing how light from a star dims as a planet passes in front of it.
A light curve from Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) shows the change in brightness of light from the WASP-96 star system over time as the planet transits the star.

In this observation, the wavelengths detected by NIRISS range from 0.6 microns (red) to 2.8 microns (in the near-infrared). The amount of starlight blocked ranges from about 13,600 parts per million (1.36 percent) to 14,700 parts per million (1.47 percent).

Researchers are able to detect and measure the abundances of key gases in a planet’s atmosphere based on the absorption pattern – the locations and heights of peaks on the graph: each gas has a characteristic set of wavelengths that it absorbs. The temperature of the atmosphere can be calculated based in part on the height of the peaks: a hotter planet has taller peaks. Other characteristics, like the presence of haze and clouds, can be inferred based on the overall shape of different portions of the spectrum.

The gray lines extending above and below each data point are error bars that show the uncertainty of each measurement, or the reasonable range of actual possible values. For a single observation, the error on these measurements is remarkably small.

The blue line is a best-fit model that takes into account the data, the known properties of WASP-96 b and its star (e.g., size, mass, temperature), and assumed characteristics of the atmosphere. Researchers can vary the parameters in the model – changing unknown characteristics like cloud height in the atmosphere and abundances of various gases – to get a better fit and further understand what the atmosphere is really like. The difference between the best-fit model shown here and the data simply reflects the additional work to be done in analyzing and interpreting the data and the planet.

Although full analysis of the spectrum will take additional time, it is possible to draw a number of preliminary conclusions. The labeled peaks in the spectrum indicate the presence of water vapor. The height of the water peaks, which is less than expected based on previous observations, is evidence for the presence of clouds that suppress the water vapor features. The gradual downward slope of the left side of the spectrum (shorter wavelengths) is indicative of possible haze. The height of the peaks along with other characteristics of the spectrum is used to calculate an atmospheric temperature of about 1350°F (725°C).

This is the most detailed infrared exoplanet transmission spectrum ever collected, the first transmission spectrum that includes wavelengths longer than 1.6 microns with such high resolution and accuracy, and the first to cover the entire wavelength range from 0.6 microns (visible red light) to 2.8 microns (near-infrared) in a single shot. The speed with which researchers have been able to make confident interpretations of the spectrum is further testament to the quality of the data.

The observation was made using NIRISS’s Single-Object Slitless Spectroscopy (SOSS) mode, which involves capturing the spectrum of a single bright object, like the star WASP-96, in a field of view.

WASP-96 b is a hot gas giant exoplanet that orbits a Sun-like star roughly 1,150 light-years away, in the constellation Phoenix. The planet orbits extremely close to its star (less than 1/20th the distance between Earth and the Sun) and completes one orbit in less than 3½ Earth-days. The planet’s discovery, based on ground-based observations, was announced in 2014. The star, WASP-96, is somewhat older than the Sun, but is about the same size, mass, temperature, and color.

The background illustration of WASP-96 b and its star is based on current understanding of the planet from both NIRISS spectroscopy and previous ground- and space-based observations. Webb has not captured a direct image of the planet or its atmosphere.

NIRISS was contributed by the Canadian Space Agency. The instrument was designed and built by Honeywell in collaboration with the Université de Montréal and the National Research Council Canada.

Source: https://exoplanets.nasa.gov/resources/2326/exoplanet-wasp-96-b-atmospheric-characteristics/

29th May 2022

The MAVEN orbiter’s main antenna is pointed toward Earth as it recovers, limiting science operations.

A navigation system glitch that struck NASA’s MAVEN orbiter at Mars earlier this year has hobbled the spacecraft’s ability to conduct science and study the Red Planet’s atmosphere.

The MAVEN spacecraft, which has orbited Mars since 2014, went into a protective “safe mode” on Feb. 22 when its vital inertial measurement units “began exhibiting anomalous behavior,” NASA officials wrote in a May 18 update. While in safe mode, a spacecraft shuts down all science and awaits instructions from its flight controllers on how to recover.

In the weeks that followed, NASA managed to revive MAVEN from safe mode, but in a limited capacity. The orbiter is in a stable orbit with its primary antenna pointed at Earth to maintain high-rate communications with its flight control team. 

“In this configuration, however, MAVEN cannot perform communications relays for other spacecraft on Mars and is performing only limited science observations,” NASA officials wrote in the update (opens in new tab). “The mission team began science instrument recovery on April 20.” The orbiter normally serves as a communication relay for NASA’s Curiosity rover and Perseverance rover on Mars to beam the latest images and research from the Martian surface to Earth.

MAVEN’s inertial measurement unit (IMU) system relies on ring laser gryroscopes, that detect the spaceraft’s inertial motion, and four reaction wheels arranged in a four-sided pyramid that can spin independently to position the orbiter in the proper orientation, according to a NASA press kit (opens in new tab). The orbiter is also equipped with two star tracker cameras that can take images of stars and feed them into a stellar detection algorithm to help the spacecraft determine its orientation in space.

NASA officials reported that MAVEN was in safe mode until April 19, when flight controllers switch the spacecraft from its IMUs to the star-tracking system in what is known as “all-stellar mode.”

“All MAVEN’s science instruments are currently online, but not all of them have been able to take data while the high gain antenna is restricted to pointing toward Earth,” NASA officials wrote in the update. “The team is currently working to finish checkouts of ‘all stellar’ mode to enable the spacecraft to operate in other orientations prior to resuming nominal science and relay operations by the end of the month.”

NASA launched the MAVEN mission (its name is short for Mars Atmosphere and Volatile EvolutioN mission) in November 2013 and arrived at the Red Planet in October 2014. Its mission is to study how Mars lost its surface water to become the dusty red world we see today. Last month, NASA extended the MAVEN mission, which originally cost $671 million, by another three years to allow the orbiter to continue its science work.

Source: https://www.space.com/mars-maven-orbiter-glitch-stalls-science

12th May 2022

An image of the supermassive black hole at the heart of the Milky Way has been captured, giving the first direct glimpse of the “gentle giant” at the centre of our galaxy.

The black hole itself, known as Sagittarius A*, cannot be seen because no light or matter can escape its gravitational grip. But its shadow is traced out by a glowing, fuzzy ring of light and matter that is swirling on the precipice at close to the speed of light.

The image was captured by the Event Horizon telescope (EHT), a network of eight radio telescopes spanning locations from Antarctica to Spain and Chile, which produced the first image of a black hole in a galaxy called Messier 87 in 2019.

Prof Sera Markoff, an astrophysicist at the University of Amsterdam and co-chair of the EHT Science Council, said: “The Milky Way’s black hole was our main target, it’s our closest supermassive black hole and it’s the reason we set out to do this thing in the first place. It’s been a 100-year search for these things and so, scientifically, it’s a huge deal.”

The image provides compelling proof that there is a black hole at the centre of the Milky Way, which had been the working assumption of mainstream astronomy. A minority of scientists had continued to speculate about the possibility of other exotic objects, such as boson stars or clumps of dark matter.

“I’m personally happy about the fact it really drills home the fact that there is definitely a black hole at the centre of our galaxy,” said Dr Ziri Younsi, a member of the EHT collaboration based at University College London.

To the untrained eye, the latest image might appear roughly similar to that of the black hole, M87*, but the two objects are extremely different, according to the EHT team.

Sagittarius A* is consuming only a trickle of material, in contrast to the typical depiction of black holes as violent, ravenous monsters of the cosmos. “If SgrA* were a person, it would only consume a single grain of rice every million years,” said Michael Johnson of the Harvard-Smithsonian Center for Astrophysics.

M87*, by contrast, is one of the largest black holes in the universe and features vast, powerful jets that launch light and matter from its poles into intergalactic space.

“Sgr A* is giving us a view into the much more standard state of black holes: quiet and quiescent,” said Johnson. “[It] is exciting because it’s common.”

The latest observations also appear to show that our black hole’s angle of rotation is not neatly aligned with the galactic plane, but is off-kilter by about 30 degrees, and hint at spectacular magnetic activity similar to that seen in the sun’s atmosphere. Beyond the science, astronomers acknowledged an emotional connection with finally seeing the enigmatic object about which our home galaxy revolves.

“It’s another doughnut, but it’s our doughnut,” said Younsi.

Despite being local in astronomical terms at 26,000 light years away, observing SgrA* turned out to be more challenging than anticipated. The team spent five years analysing data acquired during fortuitously clear skies across several continents in April 2017.

Sagittarius A* is relatively small, meaning that the dust and gas in its accretion disc orbit in a matter of minutes rather than weeks, creating a moving target from one observation to the next. Markoff compared the observations with trying to photograph a puppy chasing its tail using a camera with a slow shutter speed. Scientists also had to peer through the galactic plane and filter out intervening stars and dust clouds from their images. Some combination of these factors – and possibly some extreme black hole phenomenon – explain the bright blobs in the image.

“We didn’t anticipate how evasive and elusive it would be,” said Younsi. “It was really a tough picture to take. It’s hard to overstate that.”

The EHT picks up radiation emitted by particles within the accretion disc that are heated to billions of degrees as they orbit the black hole before plunging into the central vortex. The blotchy halo in the image shows light bent by the powerful gravity of the black hole, which is 4 million times more massive than that of our sun.

Ultimately, scientists hope that observing a range of black holes – fairly dormant ones like our own and turbulent giants like M87* – could help answer a chicken-and-egg style question about the evolution of galaxies.

“It’s an open question in galactic formation and evolution. We don’t know which came first, the galaxy or black hole,” said Prof Carole Mundell, an astrophysicist at the University of Bath who is not part of the EHT collaboration.

“From the technology perspective it’s mind-blowing that we can do this,” she said of the latest images.

The EHT team’s results are published on Thursday in a special issue of the Astrophysical Journal Letters.

Source: https://www.theguardian.com/science/2022/may/12/supermassive-black-hole-centre-milky-way-first-time-sagittarius-a-?fr=operanews

1st May 2022

Meet ignimbrite, a volcanic rock found here on Earth and potentially on Mars.

An unusual rock type spotted by two Mars rovers may indicate that the Martian landscape was shaped by extremely violent volcanic eruptions.

The Nili Fossae region of Mars, which includes the Jezero Crater that NASA’s Perseverance rover is currently exploring, is filled with bedrock laden with the volcanic mineral olivine. That same olivine-rich bedrock was also found at the Gusev Crater, where NASA’s Spirit Rover roamed until its demise in 2010. But the connection between the regions wasn’t made until now, by a team led by planetary geologist Steve Ruff of Arizona State University. The researchers examined data from multiple Mars rovers to confirm the geologic similarities, which indicates the local rocks might have formed by similar processes. Then the scientists compared Spirit’s images of the Gusev Crater rock with images of Earth rocks.

“That was a eureka moment,” Ruff said in a statement. “I was seeing the same kind of textures in the rocks of Gusev crater as those in a very specific kind of volcanic rock found here on Earth.”

That rock is ignimbrite, which is created from the ash, pumice and pyroclastic flows of powerful volcanic eruptions. “No one had previously suggested ignimbrites as an explanation for olivine-rich bedrock on Mars,” Ruff said. “And it’s possible that this is the kind of rock that the Perseverance rover has been driving around on and sampling for the past year.”

Although researchers have long theorized that volcanism was responsible for producing the Nili Fossae — olivine is, after all, a volcanic mineral — the identification of ignimbrite, if proven accurate, would indicate that the eruptions were more cataclysmic than previously thought.

“Imagine a ground-hugging cloud of hot gasses and nearly molten ash and pumice flowing through the landscape for dozens of miles and piling up in layers up to hundreds of feet thick in just a few days,” Ruff said about eruptions that have produced this type of rock on Earth.

To confirm the presence of ignimbrite on Mars, the scientists say they will have to study the rocks in a terrestrial lab another argument for the planned Mars Sample Return mission to ferry Perseverance’s samples back to Earth.

The results of this study will be published in a paper in the journal Icarus in July.

Source: https://www.space.com/mars-rock-violent-volcanic-eruption-ignimbrite

21st March 2022

Three Russian cosmonauts have arrived at the International Space Station wearing yellow flight suits with blue accents, colours that match the Ukrainian flag.

The men were the first new arrivals on the space station since the start of the Russian war in Ukraine last month.

Cosmonauts Oleg Artemyev, Denis Matveyev and Sergey Korsakov, of Russian space corporation Roscosmos, blasted off successfully from the Russia-leased Baikonur launch facility in Kazakhstan in their Soyuz MS-21 spacecraft on Friday at 8.55pm local time. They smoothly docked at the station just over three hours later, joining two Russians, four Americans and a German on the orbiting outpost.

Video of Artemyev taken as the spacecraft prepared to dock with the space station showed him wearing a blue flight suit. It was unclear what, if any, message the yellow uniforms they changed into were intended to send.

When the cosmonauts were able to talk to family back on Earth, Artemyev was asked about the suits. He said every crew chose their own.

“It became our turn to pick a colour. But, in fact, we had accumulated a lot of yellow material so we needed to use it,” he said. “So that’s why we had to wear yellow.”

Since the war started, many people have used the Ukrainian flag and its colours to show solidarity with the country.

The war has resulted in cancelled spacecraft launches and broken contracts. The Roscosmos chief, Dmitry Rogozin, has warned that the US would have to use “broomsticks” to fly into space after Russia said it would stop supplying rocket engines to US companies. Many worry, however, that Rogozin is putting decades of a peaceful off-planet partnership at risk, most notably at the space station.

Nasa administrator Bill Nelson played down Rogozin’s comments, saying: “That’s just Dmitry Rogozin. He spouts off every now and then. But at the end of the day, he’s worked with us.

“The other people that work in the Russian civilian space program, they’re professional. They don’t miss a beat with us, American astronauts and American mission control. Despite all of that, up in space, we can have a cooperation with our Russian friends, our colleagues.”

Nasa astronaut Mark Vande Hei, who on Tuesday broke the US single spaceflight record of 340 days, is due to leave the space station with two Russians aboard a Soyuz capsule for a touchdown in Kazakhstan on 30 March.

In April, another three Nasa and one Italian astronaut are set to blast off for the space station.

Source: https://amp.theguardian.com/science/2022/mar/19/russian-cosmonauts-board-iss-wearing-colours-of-ukraine-flag

28th February 2022

Russia halts Soyuz rocket launches from South America over European sanctions on Ukraine invasion

The announcement stalls Soyuz launches from French Guiana with European launch provider Arianespace

“In response to EU sanctions against our enterprises, Roscosmos is suspending cooperation with European partners in organizing space launches from the Kourou cosmodrome and withdrawing its personnel, including the consolidated launch crew, from French Guiana,” Roscosmos chief Dmitry Rogozin said in a Twitter statement on Saturday (Feb. 26) according to a translation from Russian.

The Russian space agency Roscosmos is stopping all Soyuz rocket launches from Europe’s spaceport in French Guiana due to European Union sanctions on Russia’s invasion of Ukraine. 

Russia is also recalling 87 Russian workers from Europe’s South American spaceport in French Guiana who support Soyuz rocket launches for Roscosmos and the Russian companies NPO Lavochkin a, Progress RCC and TsENKI, according to a second Twitter statement from Roscosmos.

“The issue of the departure of Russian employees is being worked out,” Roscosmos wrote. Russia’s moves come as European Union nations, the United States and other countries have levied severe economic sanctions on Russia following the country’s invasion of Ukraine on Thursday (Feb. 24). 

Russia’s Soyuz rockets are used by the European launch provider Arianespace to launch satellites from the Guiana Space Center near Kourou, French Guiana, as well as from the Baikonur Cosmodrome in Kazakhstan (where Russia regularly launches its own Soyuz missions). The most recent Soyuz rocket to launch from Guiana Space Center lifted off on Feb. 10 carrying 34 OneWeb internet satellites.

Arianespace, based in France, also uses its own European Ariane 5 heavy-lift rocket and Vega rocket for smaller launches from French Guiana. 

Arianespace’s next Soyuz launch was scheduled for early April to launch two Galileo navigation satellites into orbit for the European Union’s Galileo constellation. That mission will almost certainly be delayed due to Russia’s announcement on Saturday. 

Thierry Breton, the European Commissioner for Space, said Russia’s decision to halt Soyuz launches with Europe will not interrupt any services for users of the Galileo satellites or of the E.U.’s Copernicus Earth observation satellite program. 

“I confirm that this decision has no consequences on the continuity and quality of the Galileo and Copernicus services,” Breton said in the statement. “Nor does this decision put the continued development of these infrastructures at risk.”

Breton added that the E.U. and its member states are “ready to act decisively” in order to “protect these critical infrastructures in case of aggression,” and that it will  “continue to develop Ariane 6 and Vega C to ensure Europe’s strategic autonomy in the area of launchers.”

The Ariane 6 rocket is Europe’s successor to the Ariane 5 and is expected to make its first flight sometime later in 2022. The Vega C rocket is a follow-on to Europe’s Vega rocket that is designed to reach more orbits and carry more diverse payloads for the same cost. The European Space Agency and Arianespace are working to develop the Ariane 6 and Vega-C rockets. 

On Friday (Feb. 25), ESA Director-General Josef Aschbacher said in a statement that the European space officials were “closely monitoring what’s happening” in Ukraine while weighing any response. ESA is working closely with Russia’s space program to launch the European ExoMars rover mission to Mars later this year.

In addition to calling off Soyuz launches from French Guiana, Rogozin also announced Saturday that he no longer felt a joint Russian-U.S. collaboration on Russia’s planned Venera-D mission to Venus was necessary, given the ongoing sanctions. 

In a separate statement, Rogozin wrote that he found it “inappropriate” for any continued participation of the U.S. in the Russian Venus mission, which was slated to launch sometime in the 2020s. NASA scientists began talks with Russia to participate in the Venera-D mission in 2017. 

Source: https://www.space.com/russia-halts-soyuz-launches-french-guiana

On This Day in Space! Jan. 16, 1969: 1st docking of 2 crewed spacecraft

On January 16, 1969, two crewed spacecraft docked in orbit for the first time. 

When the Soviet Union launched the Soyuz 4 spacecraft, only one cosmonaut was on board. But it returned with a crew of three after two cosmonauts from Soyuz 5 transferred spacecrafts in orbit.

Soyuz 4 safely returned to Earth, but the one unlucky cosmonaut who was left behind in Soyuz 5 had a pretty rough landing.   

During reentry, the service module failed to separate from the descent module, and the spacecraft got turned upside-down. To top it off, the parachutes and soft-landing rockets failed to deploy properly. That cosmonaut, Boris Volynov, miraculously survived the crash — but he did lose a few teeth.

Source: https://www.space.com/39251-on-this-day-in-space.html

January 10th 2022

James Webb Space Telescope has enough fuel for way more than 10 years of science

It’s thanks to a super-precise launch, NASA says.

NASA’s newest flagship space observatory should have enough fuel to more than double its minimum mission life peering into the history of the universe, according to an agency update.

The long-awaited James Webb Space Telescope, a collaboration with the Canadian and European space agencies led by NASA, launched into space Saturday (Dec. 25) on an Ariane 5 rocket. Often billed as a successor to the agency’s iconic Hubble Space Telescope, Webb (also known as  JWST) is designed to focus on infrared light, giving astronomers a look at the earliest days of the universe. Despite an ambitious science agenda, the mission was designed with just a five-year minimum lifetime — but with the observatory finally in space, NASA is confident that it will have enough fuel to see much more use than that.

“The Webb team has analyzed its initial trajectory and determined the observatory should have enough propellant to allow support of science operations in orbit for significantly more than a 10-year science lifetime,” NASA officials wrote in a statement posted Wednesday (Dec. 29).” For comparison, the Hubble Space Telescope has lasted more than 30 years. 

James Webb Space Telescope has enough fuel for way more than 10 years of science

By Meghan Bartels published 11 days ago

It’s thanks to a super-precise launch, NASA says.

The James Webb Space Telescope fires its thruster in the second of three mid-course maneuvers in this NASA graphic.

The James Webb Space Telescope fires its thruster in the second of three mid-course maneuvers in this NASA graphic. (Image credit: NASA)

NASA’s newest flagship space observatory should have enough fuel to more than double its minimum mission life peering into the history of the universe, according to an agency update.

The long-awaited James Webb Space Telescope, a collaboration with the Canadian and European space agencies led by NASA, launched into space Saturday (Dec. 25) on an Ariane 5 rocket. Often billed as a successor to the agency’s iconic Hubble Space Telescope, Webb (also known as  JWST) is designed to focus on infrared light, giving astronomers a look at the earliest days of the universe. Despite an ambitious science agenda, the mission was designed with just a five-year minimum lifetime — but with the observatory finally in space, NASA is confident that it will have enough fuel to see much more use than that.

“The Webb team has analyzed its initial trajectory and determined the observatory should have enough propellant to allow support of science operations in orbit for significantly more than a 10-year science lifetime,” NASA officials wrote in a statement posted Wednesday (Dec. 29).” For comparison, the Hubble Space Telescope has lasted more than 30 years. 

“Incredible news! Congratulations to the team!” Thomas Zurbuchen, NASA’s associate administrator for science, wrote in a tweet also posted Wednesday. “The extra propellant is largely due to the precision of the @Arianespace Ariane 5 launch, which exceeded the requirements needed to put @NASAWebb on the right path, as well as the precision of the first mid-course correction maneuver.”

That said, the agency noted that it can’t provide a specific estimate for how long the observatory will last.

“The analysis shows that less propellant than originally planned for is needed to correct Webb’s trajectory toward its final orbit,” officials wrote in the statement. “Consequently, Webb will have much more than the baseline estimate of propellant — though many factors could ultimately affect Webb’s duration of operation.”

Webb has completed two of the three burns required to see it to its final destination; the final burn will take place nearly a month after launch and will mark the last step in the observatory’s perilous deployment process. The first maneuver occurred on Saturday after launch, with the second taking place Monday (Dec. 27).

Webb is destined to orbit a location in space known as the second Earth-sun Lagrange point, or L2, which is nearly 1 million miles (1.5 million kilometers) away from Earth in the direction opposite of the sun. Here, the telescope will be less vulnerable to solar radiation that can interfere with its infrared observations.

Lagrange points are sometimes nicknamed “parking” spots for spacecraft, as they mark locations where the gravitational tugs of different bodies balance out. However, throughout its stay at L2, Webb will need to conduct occasional small thruster burns for “station keeping” and “momentum management” to retain its proper location and orientation in space.

That’s what the propellant remaining after the third burn will be used for. And Webb will have more fuel left in its tank than NASA had dared to hope. The initial launch precisely targeted the observatory’s desired trajectory, meaning the spacecraft needed to spend less time and fuel on its first two correction maneuvers.

Source: https://www.space.com/james-webb-space-telescope-fuel-lifetime

March 4th 2019

On March 4th, 1979, NASA’s Voyager 1 spacecraft took the first photos of rings around Jupiter. This was the first time anyone had seen Jupiter’s rings.

Because Jupiter’s rings are so thin and faint, it’s extremely difficult to see them from Earth with ground-based telescopes. Even for a spacecraft out near Jupiter, the rings are essentially invisible unless the cameras look at them edge-on or from an angle where sunlight shines directly through them.

Since Voyager 1 first saw the rings, other space missions like Juno and Galileo have continued to study them. Scientists believe that the rings formed by comets colliding with Jupiter’s moons and kicking dust into the planet’s orbit.

Source: https://www.space.com/39251-on-this-day-in-space.html

Sat 17 Nov – Buying a telescope

Thinking of asking for or giving a telescope for Christmas?  Cork Astronomy Club has a word of advice to offer: don’t!  Or at least, not until you have attended our “What telescope” workshop on Saturday November 17th.

What type of telescope? Dobsonian, Newtonian, go-to? Or would binoculars be better for you? How much to spend?  Is there such a thing as a beginner’s scope?  Where do I buy it? … So many questions … and one place to get the answers …  Tony Jackson’s “What telescope” workshop on November 17th, at Tory Top Library, 2:30 pm.  Our Club has no connection whatever to any business and you will receive impartial advice from an expert amateur astronomer.  Not a Club member?  You can still come, and it’s free, but need to book, please email info@corkastronomyclub.com.